Joshua Hart, who conducted the study for his Master’s dissertation in transport planning, found that “high levels of motor traffic on residential streets are associated with poor health and weakened social cohesion among residents.”

His findings, which confirmed the results of a 1969 study by Prof. Donald Appleyard examining traffic’s impact on a neighborhood in San Francisco, were based on door-to-door interviews with 60 households on three different streets in Bristol, UK. Each street was labeled “heavy”, “medium” and “light,” depending on levels of daily motor vehicle traffic.

An average resident of a “heavy” street had fewer local friends and acquaintances compared with their neighbors on “light” streets.

The residents of “light” streets felt they had a broader “home territory,” or area where felt a sense of personal responsibility or stewardship.

Residents in “light” streets reported almost three times the number of gathering spots, compared to “medium” and “heavy” streets.

Residents on “medium” and “heavy” streets had fewer cross-street friendships than their “light” street counterparts.

First-hand quotes from Bristol residents show the dramatic differences in the quality of their social life depending on their neighborhood traffic patterns. For example, a resident on “heavy” street says, “people don’t communicate unless they have to,” whereas someone on “light” street proclaims, “there really is a sense of community – we look after each other.” Other than a lack of friendships, heavy traffic also severely impacts air pollution and creates sleep disturbances.

On his blog, “On the Level,” Hart writes, “it’s really true that cars are wrecking people’s health, quality of life, and social lives, not to mention the atmosphere of our entire planet.”